Disease relevance of PUT2

• Toxicity of external Pro and P5C supply to Arabidopsis suggested that P5C dehydrogenase (P5CDH; EC 1.2.1.12) plays a crucial role in this process by degrading the toxic Pro catabolism intermediate P5C [1].
• Within the P5C dehydrogenase domain, several areas of high identity were observed between B. japonicum, E. coli, S. typhimurium, Bacillus subtilis ipa76d, and S. cerevisiae put2 [2].

High impact information on PUT2

• We have developed an in vitro system in which the posttranslational import of Put2 (delta-pyrroline-5-carboxylate dehydrogenase), into yeast mitochondria is dependent on the addition of yeast postribosomal supernatant (PRS) [3].
• When mRNA for a nuclear-encoded yeast mitochondrial matrix protein, Put2, was translated in a wheat germ cell-free system, import into posttranslationally added yeast mitochondria was negligible [3].
• When grown on media containing urea and proline as the nitrogen source, put2-disrupted cells did not grow as well as WT cells and accumulated intracellular levels of P5C that were first detected in yeast cells and ROS [4].
• Put3p is constitutively bound to the promoters of its target genes, PUT1 and PUT2, under all conditions studied but activates transcription to the maximum extent only in the absence of rich nitrogen sources and in the presence of proline (i.e., when proline serves as the sole source of nitrogen) [5].
• PUT1 and PUT2 gene expression did not require the GLN3 activator protein for expression under either repressing or derepressing conditions [6].

Biological context of PUT2

• AAP1 was physically mapped to chromosome VIII between PUT2 and CUP1 [7].
• Here, we determined the effect of put2 disruption on yeast cell viability under freezing stress [8].
• A 26-bp sequence containing this TATA box was critical to the expression of PUT2, since a deletion of this region completely abolished transcriptional activity of the gene under both inducing and noninducing conditions [9].
• In heterologous as well as homologous gene fusions, the PUT2 UAS appeared to be responsible for uninduced as well as proline-induced levels of expression [9].
• The PUT2 gene was isolated on a 6.5-kilobase insert of a recombinant DNA plasmid by functional complementation of a put2 (delta 1-pyrroline-5-carboxylate dehydrogenase-deficient) mutation in Saccharomyces cerevisiae [10].

Associations of PUT2 with chemical compounds

• Comparison of PUT gene expression in cells grown in repressing or derepressing nitrogen sources, in the absence of the inducer proline, indicated that both PUT1 and PUT2 are regulated by nitrogen repression, although the effect on PUT2 is comparatively small [6].
• In Saccharomyces cerevisiae, the PUT1-encoded proline oxidase and the PUT2-encoded delta1-pyrroline-5-carboxylate dehydrogenase are required to convert proline to glutamate [8].
• When grown on arginine as the sole nitrogen source, the put2 disruptant showed a significant decrease in cell viability after freezing despite the high proline and arginine contents [8].
• The PUT2 gene, believed to encode delta 1-pyrroline-5-carboxylate dehydrogenase, has been completely sequenced [11].
• The amino acid sequences of nine tryptic peptides (containing altogether 105 amino acids) from human liver glutamic gamma-semialdehyde of dehydrogenase (hitherto designated as ALDH4) were found to correspond, at 33-66% identity, to segments from the yeast 1-proline-5-carboxylate (P5C) dehydrogenase encoded by the PUT2 gene [12].

Regulatory relationships of PUT2

• The PUT1 and PUT2 genes encoding the enzymes of the proline utilization pathway of Saccharomyces cerevisiae are induced by proline and activated by the product of the PUT3 gene [13].

Other interactions of PUT2

• Recessive mutations in URE2 elevated expression of the PUT1 and PUT2 genes 5- to 10-fold when cells were grown on a nitrogen-repressing medium [6].
• In Saccharomyces cerevisiae, the ability to use proline as a nitrogen source requires the Put3p transcriptional regulator, which turns on the expression of the proline utilization genes, PUT1 and PUT2, in the presence of the inducer proline and in the absence of preferred nitrogen sources [14].
• Although located immediately adjacent to the PUT2 UAS, the TATA box did not appear to play a regulatory role, as indicated by the results of experiments in which it was replaced by the CYC7 TATA box [9].
• Its identity was confirmed by a gene disruption technique in which the chromosomal PUT2+ gene was replaced by plasmid DNA carrying the put2 gene into which the S. cerevisiae HIS3+ gene had been inserted [10].

References